Cone-beam computed tomography or CBCT scanning makes it possible to improve image capture and processing speeds by directing a cone-beam source through the patient or other subject to obtain an image on a flat-panel X-ray detector. In cone-beam computed tomography scanning, a volume or 3-D image is reconstructed from numerous individual scan projections, each taken at a different angle, whose image data is aligned and processed in order to generate and present data as a collection of volume pixels or voxels.
Generation of scatter in X-ray radiographic and flat panel based CT imaging is very complex. Incident X-ray photons are scattered inside the object, and when scattered photons reach the detector, an overestimation of the registered total intensity in each projection, which can be equivalent to an underestimation of attenuation coefficients associated with the materials inside the object, can result. Scatter may lead to image artifacts such as “cupping” in homogeneous object or dark streaks between image regions of high attenuation. As a result of the contamination of collected data with scattered photons, the low-contrast detectability of a CBCT system is decreased.
Related art scatter correction methods can include hardware scatter rejection (e.g., systems equipped with bowtie filter and/or anti-scatter grids), measurement of scatter using beam stop methods, or image processing methods (e.g., software applications) such as Monte Carlo modeling of photon transport through the patient, convolution-superposition methods, analytical scatter models, heuristic methods based on approximate geometry; or image enhancement methods.
Cone-beam computed tomography (CBCT) scanning is of significant interest for applications such as biomedical, dental, and industrial applications.
Improved scatter correction or image processing methods of scatter correction on projection images that can reduce artifacts in the reconstructed image domain is desirable. There is a compelling need for improved methods for scatter correction in volume imaging techniques.